U.S. Pat. No. 5,372,924 discloses an antistatic element comprising: a plastic support having a surface; a first layer on the surface of said plastic support, said first layer being polythiophene made up of units of the formula
in which R1 and R2 independently of one another represent hydrogen or a C1-4 alkyl group or, together form an optionally substituted C1-4 alkylene radical, preferably an optionally alkyl-substituted methylene radical, an optionally C1-12 alkyl- or phenyl-substituted 1,2-ethylene radical, a 1,3-propylene radical or a 1,2-cyclohexylene radical and An− is a polyanion; and a second layer, said second layer being a prepolymer which is curable by exposure to ionizing radiation.
U.S. Pat. No. 6,004,483 discloses a mixture of a polythiophene preparation which contains a polythiophene salt polythiophene+ An− in which the polythiophene+ of the polythiophene salt contains positively charged and uncharged recurring units of the formula
in which R1 and R2 independently of one another stand for hydrogen or a C1-C4 alkyl group or together form an optionally substituted C1-C4 alkylene radical, and An− denotes a polyanion, and a coating composition which contains a (meth)acryloyl group-containing prepolymer which contains per molecule at least two (meth)acryloyl groups and which is curable by ionizing radiation. U.S. Pat. No. 6,004,483 further discloses that examples of suitable radiation-curable coating compositions are (meth)acryloyl group-containing prepolymers which contain per molecule at least two (meth)acryloyl groups, preferably from two to four (meth)acryloyl groups, and which derive from polyesters, polyethers, polyepoxide compounds, aliphatic polyols, polyurethanes and vinyl polymers. U.S. Pat. No. 6,004,483 also discloses that preferred (meth)acrylate prepolymers are polyester (meth)acrylates such as are obtained by azeotropic esterification of dicarboxylic acids with di- or higher-functional polyols and (meth)acrylic acid and that amine-modified polyether acrylates, such as are obtained according to DE-OS 3 706 355 from aliphatic primary amines and (meth)acrylic acid esters of ethoxylated or propoxylated polyols, may furthermore be utilized as prepolymers which contain (meth)acryloyl groups. Furthermore, U.S. Pat. No. 6,004,483 discloses invention examples in which poly(3,4-ethylenedioxythiophene)-containing layers coated from an aqueous medium are UV-cured.
U.S. Pat. No. 6,099,757 discloses a composition comprising: a) from about 80 to 99.5 percent by weight of a functionalized film-forming polymer matrix; and b) from about 0.5 to 20 percent by weight of an intrinsically conductive polymer dispersed in said matrix; wherein the functionalized film-forming matrix controls the electrical conductivity in said composition within a range of less than 5 orders of magnitude from about 105 to about 1010 ohm/square and is selected from the group consisting of acrylates and methacrylates containing at least one functionality selected from the group consisting of urethane, epoxy, glycol, hydroxyl, polyester, ethoxylates and propoxylates. U.S. Pat. No. 6,099,757 further discloses that the intrinsically conductive polymer may be selected from the group consisting of polyanilines, polythiophenes, polypyrroles, poly(phenylene vinylenes), poly(arylene vinylenes), poly(isothianaphthalenes), and substituted derivatives thereof and that composition may be curable with high energy radiation electron beams, X-rays, UV-radiation, microwave radiation, infrared radiation, corona discharge, gamma rays and heat. Furthermore, U.S. Pat. No. 6,099,757 discloses invention examples in which polyaniline-containing layers coated from a non-aqueous medium are UV-cured. U.S. Pat. No. 6,099,757 fails to disclose specific substituted polythiophenes.
U.S. Pat. No. 6,193,909 discloses a structure comprising: a composition comprising precursors to an electrically conductive polymer wherein said precursor comprises covalent crosslinks and solvent solvating enhancing functionality said crosslinkable functionality is selected from the group consisting of hydrogen bonding functionality and chemical cross-linkable functionality selected from the group consisting of hydroxyethyl and hydroxymethyl groups.
In 2002, Y-B Kim et al. in Polymers for Advanced Technologies, volume 13(7), pages 522-526, reported UV-cured transparent films containing conductive microgels coated with polyaminiline/dodecyl-benzenesulponic acid (DBSA).
JP 11-172103A discloses a composition obtained by compounding (A) a polyaniline derivative obtained by doping 1-10 mol. % of an aniline structure constituting the polyaniline with a sulfone-containing compound having an unsaturated double bond and (B) a photopolymerization initiator (e.g. benzoin or benzil), and preferably (C) an acrylate and/or methacrylate [e.g. diethylene glycol (meth)acrylate)], the sulfone group-containing compound having an unsaturated double bond being preferably 2-acrylamide-2-methylpropanesulfonic acid. Furthermore, JP 11-172103A discloses invention examples in which polyaniline-containing layers coated from a non-aqueous medium are UV-cured.
WO 02/06898A discloses a material for making an electroconductive pattern, said material comprising a support and a light-exposure differentiable element, characterized in that said light-exposure differentiable element comprises an outermost layer containing a polyanion and a polymer or copolymer of a substituted or unsubstituted thiophene, and optionally a second layer contiguous with said outermost layer; and wherein said outermost layer and/or said optional second layer contains a light-sensitive component capable upon exposure of changing the removability of the exposed parts of said outermost layer relative to the unexposed parts of said outermost layer. WO 02/069898A discloses invention examples in which poly(3,4-ethylenedioxy-thiophene)-containing layers coated from an aqueous medium are UV-crosslinked and electroconductive layers with surface resistances down to 480 Ω/square are reported, this surface resistance being realized in the absence of binder with a layer coated with the following composition:
1.2% aqueous dispersion of PEDOT/PSS =417 g0.25% aqueous solution of diazo resin No. 8 from FAIRMOUNT100 gCHEMICAL =2% aqueous solution of ZONYL ™ FSO 100 = 10 gN-methyl-pyrrolidinone = 50 gdeionized water =423 gupon exposure in a PRINTON™ CDL 1502i UV contact exposure unit (from AGFA-GEVAERT N.V.) for 30-75 s at 2 mW/cm2 (=exposure of 0.06-0.15 J/cm2).
WO 03/001537A discloses a material for making an electroconductive pattern, said material comprising a support and a light-exposure differentiable element, characterized in that said light-exposure differentiable element comprises a conductivity enhanced outermost layer containing a polyanion and a polymer or copolymer of a substituted or unsubstituted thiophene, and optionally a second layer contiguous with said outermost layer; and wherein said outermost layer and/or said optional second layer contains a monodiazonium salt capable upon exposure of reducing the conductivity of the exposed parts of said outermost layer relative to the unexposed parts of said outermost layer. WO 03/001537A discloses invention examples in which poly(3,4-ethylene-dioxythiophene)-containing layers coated from an aqueous medium are UV-crosslinked with monodiazo-compounds with resulting increase in surface resistance.
U.S. Pat. No. 6,399,675 discloses a method for preparing an electrically conductive microgel comprising, on the basis of the electrically conductive microgel, adding 3 to 30% weight % of a monomer for synthesizing an electrically conductive polymer and 1 to 20 weight % of a dopant to 15 to 80 weight % of an organic solution containing 5 to 60% weight % of microgel particles based on the organic solution; and polymerizing said monomer at a temperature of 0 to 80° C. with the addition of 2 to 40 weight % of an aqueous solution containing 1 to 40 weight % of an oxidative polymerization catalyst based on the aqueous solution in which the polymer is adsorbed on the surface of the microgel particles. U.S. Pat. No. 6,399,675 further discloses that for coating application, the electrically conductive microgel of the present invention may be combined with various binders, depending on the electrical conductivity and physical properties required for the coating, in association with a binder, the microgel can be maintained in a three dimensional structure when being dried (in the form of paint) e.g. polyurethane resins, polyacrylic resins, thermosetting alkyd resins, and radiation curing vinyl monomers or oligomers.
US 2006/0008742A1 discloses a process for producing an electroluminescent element, comprising repeating at least twice the step of forming an electroluminescent layer comprising a buffer layer and a luminescent layer by patterning using a photolitho-graphic process, thereby producing an electroluminescent element comprising a patterned electroluminescent layer, said process comprising the steps of: forming a first pattern part comprising a first buffer layer as the lowermost layer; and coating a solution for second buffer layer formation in a region including said first pattern part, said first buffer layer being immiscible with said solution for second buffer layer formation. US 2006/0008742A1 further discloses that the first buffer layer can be formed from a coating liquid for buffer layer formation, comprising at least a photocatalyst and a heat- and/or photo-curable binder, the first buffer layer being formed from a water soluble coating liquid for buffer layer formation, and a first luminescent layer being formed from a non-aqueous coating liquid for luminescent layer formation. Furthermore, US 2006/0008742A1 discloses that the water soluble coating liquid for buffer layer formation may contain an organic material, which can be poly-3,4-alkenedioxythiophene with polystyrenesulfonic acid, or a derivative thereof. No information concerning the electrical conductivity of such buffer layers is provided in US 2006/0008742A.
WO 2006/080639A1 discloses an electrically conductive and scratch-resistant UV-curable composition with conductivity and scratch resistance, which comprises 4-5.9% by weight of a polythiophene-based conductive polymer aqueous solution having 1.3% by weight of solids, 7-9.9% by weights of a UV-oligomer, 82-88% by weight of an organic solvent, 0.4-0.8% by weight of a photoinitiator, and 0.2-0.05% by weight of a scratch-resistant additive, wherein the organic solvent is at least one selected from the group consisting of n-propylalcohol, methyl cellosolve, propyleneglycolmethyl ether, and diacetonealcohol, wherein the photoinitiator is selected from the group consisting of α-hydroxycyclohexylphenyl-methanone, 1-hydroxycyclohexylmethylaceto-phenone, benzophenone and benzoin, and wherein the scratch-resistant additive is ethoxylated silicone and wherein when formed into a coating film, the UV-curable composition has a hardness of 4H or more, a surface resistance of less than 107 Ω/square and a visible light transmittance of more than 96%. 4 to 5.9% by weight of a polythiophene-based conductive polymer aqueous solution having 1.3% by weight of solids corresponds to a concentration of polythiophene in the UV-curable composition of <0.052 to <0.0767% by weight, since the concentration of 1.3% by weight corresponds to all solids not just polythiophene. WO 2006/080639A1 also discloses an electrically conductive and scratch-resistant UV-curable composition with conductivity and scratch resistance, which comprises 4-5.9% by weight of a polythiophene-based conductive polymer aqueous solution containing 1.3% by weight of solids doped with polystyrene sulfonate, 7-9.9% by weights of a mixture of U-DPPA and DPHA, 82-88% by weight of an organic solvent, 0.4-0.8% by weight of α-hydroxycyclohexylphenyl-methanone as a photoinitiator, and 0.2-0.05% by weight of ethoxylated silicone as a scratch-resistant additive, and when formed into a coating film, has a hardness of 4H or more, a surface resistance of less than 107 Ω/square and a visible light transmittance of more than 96%. 4 to 5.9% by weight of a polythiophene-based conductive polymer aqueous solution containing 1.3% by weight of solids doped with polystyrene sulfonate corresponds to a concentration of polythiophene in the UV-curable composition of <0.052 to <0.0767% by weight, since this weight includes polystyrene sulfonate.
WO 07/061,559A2 discloses an electrically conductive composition comprising a photopolymer and an electrically conductive polymer dissolved or dispersed in a solvent system, said electrically conductive polymer comprising thiophene monomers. The PEDOT/PSS dispersions used in the EXAMPLES were BAYTRON® P, a 1.2% by weight of PEDOT/PSS (1:2.46 by weight) in water and BAYTRON® P HS, a 4.0% by weight dispersion of PEDOT/PSS (1:2.46 by weight) in water with water concentrations in the compositions of greater than 40 wt % and PEDOT-concentrations of 0.08 to 0.2 wt %.
WO 02/067273A1 discloses a method for exchanging solvent in a mixture comprising water and an optionally substituted polythiophene, the method comprising: a) heating at least one solvent in a vessel under conditions suitable for vaporizing water; b) contacting the heated solvent with the mixture comprising water and optionally substituted polythiophene, the contact being sufficient to remove at least part of the water from the mixture as vapor; and c) exchanging the water removed from the mixture with the solvent.
WO 02/072660A1 discloses a process for preparing a dispersion or a solution containing an optionally substituted polythiophene in an organic solvent, comprising: a) adding a water-miscible organic solvent or a water-miscible solvent mixture to an aqueous dispersion or solution comprising optionally substituted polythiophenes; and b) removing at least some of the water from the mixture resulting from step a), and thereby forming the dispersion of the solution; and a dispersion or a solution comprising a polythiophene+ An− ion complex, wherein the polythiophene+ is a polymer comprising recurring units of the formula (I):
at least some of which are positively charged and wherein Y is —(CH2)m—CR1R2(CH2)n— or an optionally substituted 1,2-C3-C8-cycloalkylene radical, and R1 and R2, independently of one another, are hydrogen, hydroxymethyl, an optionally substituted C1-C20-alkyl radical or an optionally substituted C6-C14-aryl, and m and n are identical or different and are an integer from 0 to 3, and wherein An− is an anion of an organic polyacid, in a low-water-content or an anhydrous organic solvent.
WO 02/072714 discloses solutions and/or dispersions of organic semiconductors in a solvent mixture of at least two different organic solvents, characterized in that (A) each of the solvents on its own exhibits a boiling point below 200° C. and a melting point less than or equal to 15° C., (B) at least one of the solvents exhibits a boiling point between 140° C. and 200° C., (C) the solvents used do not contain benzylic CH2- or CH-groups, (D) the solvents used are not benzene derivatives, which contain tertiary butyl substituents or more than two methyl substituents.
WO 03/048228A1 discloses a method for preparing a composition containing between 0.08 and 3.0% by weight of a polymer or copolymer of a 3,4-dialkoxythiophene in which said two alkoxy groups may be the same or different or together represent an optionally substituted oxy-alkylene-oxy bridge, a polyanion and at least one non-aqueous solvent, from a dispersion of said polymer or copolymer of (3,4-dialkoxythiophene) and said polyanion in water which is prepared in the substantial absence of oxygen, comprising in the following order the steps of: i) mixing at least one of said non-aqueous solvents with said aqueous dispersion of said polymer or copolymer of (3,4-dialkoxythiophene) and said polyanion; and ii) evaporating water from the mixture prepared in step i) until the content of water therein is reduced by at least 65% by weight.
WO 03/048229A1 discloses a method for preparing a composition containing between 0.08 and 3.0% by weight of a polymer or copolymer of a 3,4-dialkoxythiophene in which said two alkoxy groups may be the same or different or together represent a oxy-alkylene-oxy bridge optionally substituted with substituents selected from the group consisting of alkyl, alkoxy, alkyoxyalkyl, carboxy, alkylsulphonato, alkyloxyalkylsulphonato and carboxy ester groups, a polyanion and at least one polyhydroxy non-aqueous solvent from a dispersion of said polymer or copolymer of (3,4-dialkoxythiophene) and said polyanion in water comprising in the following order the steps of: i) mixing at least one of said non-aqueous solvents with said aqueous dispersion of said polymer or copolymer of (3,4-dialkoxythiophene) and said polyanion; and ii) evaporating water from the mixture prepared in step i) until the content of water therein is reduced by at least 65% by weight.
The prior art in respect to the UV-curing of polythiophene and substituted polythiophene-containing layers exclusively concerns layers coated from an aqueous medium i.e. a medium having at least 50% by weight of water. However, water evaporates from such screen printing inks resulting in clogging of the mesh and thicker conductive layers and prints produced with aqueous UV-curable inks with a polythiophene concentration greater than 0.1% by weight of polythiophene and/or substituted polythiophene exhibit poor quality prints with high haze.